Breeding wastewater treatment method and device based on red mud-boric sludge synergistic struvite petrifaction

Abstract

The invention provides a culture wastewater treatment method and device based on red mud-boric sludge synergistic struvite petrifaction, and the method comprises the following steps: firstly, adjusting the pH value of culture wastewater subjected to solid-liquid separation to 5.5-7.0, adding boric sludge accounting for 1-5% of the volume of the wastewater and having a particle size of less than or equal to 200 meshes, stirring for 10-60 minutes, promoting the boric sludge to release active Mg < 2 + > by using a weak acid environment, and synchronously separating out amorphous silicic acid / silica gel. Then adding a red mud-boric sludge compound, maintaining the pH value to be 8.5-9.5, and reacting for 20-60 minutes, so that NH4 < + >, PO4 < 3-> and Mg < 2 + > are combined to generate struvite; the pH of the compound agent is continuously increased to 9.0-10.0 to create an optimal crystallization window, red mud free Ca < 2 + > promotes sedimentation and forms calcium-doped struvite, and hematite induces Fe < 3 + > and PO4 < 3-> to generate FePO4 heterogeneous coprecipitation cores. The inner layer is a Fe-O-P chemical bonding layer, the middle layer forms a 50-200nm amorphous silica gel coating layer, and the outer layer establishes a Ca-O-Si bridging network, so that the nitrogen and phosphorus release period is remarkably delayed.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and specifically provides a method and a device for treating aquaculture wastewater based on red mud-boron mud coordinated guano petrification. Background Art

[0002] In recent years, with the large-scale and intensive development of the aquaculture industry, the discharge of aquaculture wastewater has increased dramatically, causing serious pollution to the environment. Aquaculture wastewater contains high concentrations of organic matter, ammonia nitrogen, phosphorus and other pollutants. Among them, ammonia nitrogen is one of the main pollutants in aquaculture wastewater, and its concentration is often high. High concentrations of ammonia nitrogen will not only cause eutrophication of water bodies, leading to massive reproduction of algae and destroying the balance of the water ecosystem, but will also have toxic effects on farmed animals themselves, affecting their growth and health. Traditional aquaculture wastewater treatment methods, such as physical and chemical methods (including precipitation, filtration, adsorption, etc.) and biological treatment methods (such as activated sludge method, biological filter, etc.), although they can remove pollutants in wastewater to a certain extent, these methods often have problems such as high treatment costs, complex operations, and unsatisfactory removal of high-concentration ammonia nitrogen, making it difficult to meet the current demand for efficient treatment of aquaculture wastewater.

[0003] At the same time, the aluminum and borate industries generate over 100 million tons of solid waste annually, including red mud and boron mud. Its strong alkalinity and heavy metal content lead to increasingly serious problems with waste storage and land occupation. Boron mud is discharged from factories in a wet form, with a moisture content of 30-35%. It is a brownish-brown mud (when wet), with a fine particle size and containing unreacted magnesium ore. After drying, it forms lumps of mud that are somewhat plastic and easily broken and ground. In my country, red mud is classified as Category II general industrial solid waste.

[0004] Red mud is an insoluble residue. Its sources can be categorized as sintered red mud, Bayer process red mud, and combined process red mud. With the increasing amount of red mud stockpiles and the increasingly serious environmental pollution it causes, its resource utilization has become urgent. A major characteristic of red mud is its high alkalinity. Its pH typically ranges from 10 to 13. Alkaline substances in red mud can be divided into soluble chemical alkalis and insoluble structural alkalis. Residual alkali in red mud primarily exists in the form of NaOH, Na2CO3, NaAl(OH)4, Na2SiO3, and Ca(OH)2. These are primarily generated or added during the leaching process. Soluble chemical alkalis dissolve readily, forming alkaline anions, resulting in a higher pH value for the red mud. In addition to its strong alkalinity, red mud also possesses high water content, low shear strength, high compressibility, and good plasticity. Other metallic elements contained in bauxite primarily include iron, silicon, magnesium, titanium, calcium, and their oxides. Vanadium, gallium, phosphorus, nickel, and germanium are present at very low levels. Red mud produced during various alumina production processes contains not only the aforementioned impurities and undissolved aluminum oxides, but also red mud with varying compositions due to the addition of lime or other substances in the production process. Therefore, the comprehensive treatment and utilization of red mud has become a global technological challenge. Large amounts of red mud remain unutilized and must be stored in extensive storage yards, occupying significant land and causing serious environmental pollution. Therefore, minimizing the harmful effects of red mud and achieving multi-channel, large-scale resource utilization is imperative.

[0005] The main component of struvite is magnesium ammonium phosphate hexahydrate (MgNH4PO4·6H2O). Magnesium ammonium phosphate hexahydrate is a white powder with a relative density of 1.711. It is a composite slow-release fertilizer containing multiple elements, including nitrogen, phosphorus, and magnesium. Magnesium ammonium phosphate hexahydrate has low solubility in water. Under suitable soil temperature conditions, it slowly decomposes through nitrification by microorganisms, thus providing nutrients to plants. Due to its slow-release properties and resistance to leaching, struvite is particularly suitable for fertilizing plants growing in magnesium-deficient sandy soils prone to leaching, as well as in magnesium-deficient, hot, and rainy areas. Struvite is also particularly suitable for fertilizing crops in inland lake areas, offering broad application prospects for reducing agricultural non-point source pollution and improving lake eutrophication. Struvite also improves soil structure and promotes soil microbial activity.

[0006] In this context, the "waste treatment with waste" technology route has gradually matured - using the alkaline neutralization effect of red mud, the magnesium element release characteristics of boron mud and the struvite crystallization method, it can not only achieve efficient recovery of nitrogen and phosphorus in aquaculture wastewater, but also dispose of two types of industrial solid waste.

[0007] Therefore, a new aquaculture wastewater treatment solution based on red mud-boron mud synergistic guano petrification is urgently needed to solve the above problems. Summary of the Invention

[0008] In order to overcome the above-mentioned drawbacks, the present invention is proposed to provide a solution or partial solution to the above-mentioned problems.

[0009] In one aspect, the present invention provides a method for treating aquaculture wastewater based on red mud-boron mud synergistically with guano petrification, comprising the following steps: S1, after solid-liquid separation of the aquaculture wastewater to be treated, adjusting the pH to 5.5-7.0, adding boron mud and stirring for 10-60 minutes, the boron mud is hydrolyzed in the weakly acidic environment of the wastewater to release active Mg 2+ , among which part of the amorphous silicon will be precipitated in the form of silicic acid or silica gel; S2, add red mud-boron mud compound agent, maintain to pH8.5-9.5, react for 20-60 minutes, make NH4 + With PO4 3 - Under alkaline conditions with Mg 2+ Combine; continue to add compounding agent, free Na in red mud + OH - Rapidly increase the pH of wastewater to 9.0-10.0 to create the best crystallization window for struvite; at the same time, a small amount of hematite Fe2O3 plays the role of inducing eutectic: Fe 3+ With PO4 3- FePO4 is generated, and the lattice forms a heterogeneous coprecipitation nucleus with struvite MgNH4PO4. Free calcium ions accelerate the sedimentation of struvite. Ca 2+ Entering the struvite lattice to form calcium-doped struvite Ca x Mg 1-x NH4PO4; S3, the treatment liquid is aged at 50-70°C for 2-4 hours, so that the product forms a stabilized structure of Fe-OP chemical bonding layer, silica gel physical coating layer, and Ca-O-Si bridging network layer from the inside to the outside.

[0010] In a technical solution of the above-mentioned aquaculture wastewater treatment method based on red mud-boron mud synergistic guano petrification, the addition amount of the boron mud in S1 is 1-5% of the wastewater volume, and the boron mud particle size is ≤200 mesh.

[0011] In a technical solution of the above-mentioned aquaculture wastewater treatment method based on red mud-boron mud coordinated guano petrification, the composition of the red mud-boron mud compound is as follows by weight percentage: 50-80% red mud, 20-50% boron mud, 0.5-2% polyaspartic acid, and 1-3% sodium carbonate.

[0012] In a technical solution of the above-mentioned aquaculture wastewater treatment method based on red mud-boron mud synergistic guano petrochemical, the triple packaging structure formed in S3 satisfies the following requirements: inner layer: Fe-OP chemical bonding layer, Raman spectrum characteristic peak is located at 1085-1093cm -1 ; Middle layer: amorphous silica coating SiO2·nH2O, thickness 50-200nm; outer layer: Ca 2+ Bridged Ca-O-Si network structure, Ca / Mg molar ratio 0.1-0.3.

[0013] On the other hand, the present invention provides an aquaculture wastewater treatment device based on red mud-boron mud coordinated guano petrification, comprising: a reaction tank, a solid-liquid separation module, a dynamic control unit and a disinfection module; wherein, a multi-source sensor array is deployed in the reaction tank for real-time collection of time series data of wastewater turbidity, pH value, temperature, water level, conductivity concentration and stirring power; the solid-liquid separation module is installed in the reaction tank, comprising an ultrasonic enhancement zone, a progressive pressure dehydration zone, a special filter belt and a non-contact air knife stripper; the dynamic control unit outputs a crystallization time prediction value and a wrapping degree prediction value based on the time series data as input; during operation, the dynamic control unit determines whether to start the solid-liquid separation unit based on the crystallization time prediction value; the dynamic control unit adjusts the amount of polyaspartic acid added based on the wrapping degree prediction value; the disinfection module comprises: an ultraviolet LED array and an ozone microbubble generator.

[0014] In a technical solution of the above-mentioned aquaculture wastewater treatment device based on red mud-boron mud and guano petrification, the ultrasonic enhancement zone is provided with a transducer array, and the transducer array dynamically adjusts the action time according to the water level change; the pressure gradient of the progressive pressure dehydration zone is 0.3 bar to 1.5 bar turbidity; when the turbidity is greater than the preset turbidity value, the ultrasonic power is increased to the preset power value, and the pressure is reduced to the preset pressure value at the same time; the third-order pressure gradient is dynamically selected based on the predicted value of the encapsulation degree, and the selection of the third-order pressure gradient is associated with the numerical range of the predicted value of the encapsulation degree, that is, according to the different intervals in which the predicted value of the encapsulation degree is located, the preset third-order pressure gradient parameter combination is matched.

[0015] In a technical solution of the above-mentioned aquaculture wastewater treatment device based on red mud-boron mud coordinated guano petrification, the dynamic selection of the third-order pressure gradient based on the predicted encapsulation value specifically includes: when the predicted encapsulation value is ≥0.85, adjusting the pressure gradient to 0.3→0.8→1.0 bar; when the predicted encapsulation value is 0.75-0.85, adjusting the pressure gradient to 0.5→1.0→1.3 bar; when the predicted encapsulation value is <0.75, adjusting the pressure gradient to 0.8→1.2→1.5 bar.

[0016] In a technical solution of the above-mentioned aquaculture wastewater treatment device based on red mud-boron mud synergistic guano petrification, for mammalian wastewater, when its ammonia nitrogen concentration is 200-1500 mg / L and COD is 5000-30000 mg / L, the weight ratio of red mud to boron mud is controlled to be 1:(0.5-1), and the reaction pH is maintained. 8.5–9.0; if heavy metals are detected > the limit, increase the amount of red mud by 10–20%; for crustacean wastewater, when the salinity is 3000–35000μS / cm and the antibiotic residue is 1.5–5mg / L, implement: when the salinity is > 5000μS / cm, increase the amount of boron mud by 15-25%; activate the disinfection module to degrade antibiotics, and adjust the ozone concentration to 0.4mg / L × antibiotic concentration; for fish wastewater, when the suspended solids SS is 800–5000mg / L and the total phosphorus TP is 20–200mg / L, add a vortex flotation pretreatment unit with an air-water ratio of 0.5:1 and a removal rate of > 80%; for amphibian wastewater, when the pathogenic microorganism load is detected to be 10 3 –10 6 CFU / mL, and extend the disinfection time of the disinfection module by at least 1.5 times.

[0017] In a technical solution of the above-mentioned aquaculture wastewater treatment device based on red mud-boron mud coordinated guano petrification, the dynamic control unit determines whether to start the solid-liquid separation unit based on the predicted value of the crystallization time, and then includes: if the real-time operation time is ≥ the predicted value of the crystallization time, the solid-liquid separation unit is triggered to start, and the real-time operation time refers to the operation time of the equipment from the input of the compounding agent to the end of the aging process.

[0018] In a technical solution of the above-mentioned aquaculture wastewater treatment device based on red mud-boron mud coordinated guano petrochemicalization, the dynamic control unit adjusts the dosage of polyaspartic acid based on the predicted value of the encapsulation degree, including: if the predicted value of the encapsulation degree is less than the preset encapsulation degree value, then increase the dosage of polyaspartic acid by 0.3-0.5wt%; if the predicted value of the encapsulation degree is greater than or equal to the encapsulation degree, then maintain the current dosage.

[0019] The beneficial effects of the aquaculture wastewater treatment method based on red mud-boron mud synergistic struvite provided by the present invention are as follows: the method utilizes the synergistic effect of red mud and boron mud, greatly accelerating the struvite formation process, not only shortening the reaction time, but also increasing the amount and purity of struvite generated. In addition, it effectively extends the fertilizer effect cycle and improves resource utilization: the triple packaging structure formed extends the nitrogen and phosphorus release cycle of struvite, thereby improving resource utilization. The fertilizer effect cycle is extended from the traditional several weeks to several months or even longer. This not only reduces the number of times and amounts of fertilizer are applied, reducing agricultural production costs, but also avoids problems such as soil pollution and water eutrophication caused by excessive fertilizer application, thereby improving the sustainability of agricultural production. At the same time, extending the fertilizer effect cycle also enables the nutrients in struvite to be more fully absorbed and utilized by crops, improving resource utilization, and achieving a win-win situation in economic and environmental benefits.

[0020] The supporting treatment device collects parameters such as turbidity, pH, and conductivity of the reaction tank in real time through a multi-source sensor array, and the bidirectional long short-term memory network (BiLSTM) model synchronously predicts the crystallization time and encapsulation degree: when the real-time running time ≥ the predicted value, solid-liquid separation is triggered, and when the predicted encapsulation degree is <0.85, the amount of polyaspartic acid is increased by 0.3-0.5% (of the total weight of the system). The solid-liquid separation module adopts the linkage of the ultrasonic enhancement zone and the progressive pressure dehydration zone, dynamically selects the third-order pressure gradient according to the predicted encapsulation degree, and cooperates with the special PTFE filter belt and air knife stripper to achieve efficient separation. After disinfection, the purified water is reused for flushing or irrigation to form a zero-emission closed loop. This technology reduces the treatment cost through the synergy of solid and waste, improves the stability of the product through calcium doping and triple encapsulation, and realizes precise control through intelligent models, ultimately achieving the recycling of waste resources.

[0021] Furthermore, standardized and precise control is achieved, and the operational stability and reliability of the device are improved. The present invention uses the intelligent prediction and adjustment functions of the dynamic control unit to achieve standardized and precise control of the wastewater treatment process, reducing dependence on manual experience. This intelligent control method not only improves the operating efficiency of the wastewater treatment system, but also greatly enhances the stability and reliability of the system. Even in the case of large fluctuations in wastewater quality or changes in treatment load, the dynamic control unit can make timely adjustments to ensure that the wastewater treatment effect always remains at a stable level. At the same time, standardized and precise control also reduces the skill requirements of operators, reduces the impact of human factors on system operation, and improves the degree of automation and management level of the wastewater treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The disclosure of the present invention will be more easily understood with reference to the accompanying drawings. Those skilled in the art will readily appreciate that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Furthermore, similar numbers in the drawings represent similar components, wherein:

[0023] Figure 1 This is a schematic diagram of the aquaculture wastewater treatment process based on red mud-boron mud coordinated guano petrification according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] Some embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0025] The present invention provides a method for treating aquaculture wastewater based on red mud-boron mud coordinated with guano petrification, comprising the following steps:

[0026] S1. After solid-liquid separation, the aquaculture wastewater to be treated is adjusted to pH 5.5-7.0, and boron mud is added and stirred for 10-60 minutes. The boron mud is hydrolyzed in the weakly acidic environment of the wastewater to release active Mg. 2+ , in which part of the amorphous silicon will be precipitated in the form of silicic acid or silica gel;

[0027] In this embodiment, first, the aquaculture wastewater undergoes solid-liquid separation to remove large particles of solid impurities, completing the pretreatment stage and reducing the difficulty of subsequent treatment. Then, the pretreated aquaculture wastewater is discharged into the reaction tank. Dilute sulfuric acid (concentration of 10-20%) is used as a pH regulator and is accurately added to the reaction tank via a metering pump. During the pH adjustment process, an online pH meter monitors the pH value of the wastewater in real time. When the pH value reaches the set range, the addition of dilute sulfuric acid is automatically stopped. To prevent local over-acidity or over-alkalinity during the pH adjustment process, a multi-point dosing device is set in the reaction tank to ensure that the dilute sulfuric acid is evenly mixed with the wastewater. At the same time, the stirring device is turned on, the stirring speed is controlled at 50-100r / min, and the stirring time is 5-10 minutes to ensure uniform pH adjustment. The pH of the wastewater is adjusted to 5.5-7.0. Boron mud is accurately weighed at a ratio of 1-5% of the wastewater volume and evenly added to the reaction tank via a screw conveyor. The stirring device is turned on, the stirring speed is increased to 150-200r / min, and the stirring time is 10-60 minutes. During the stirring process, the Mg content in the wastewater was regularly tested. 2+ When the concentration of Mg 2+ When the concentration reaches 50-100 mg / L, it means that the boron sludge is fully hydrolyzed. In a weakly acidic environment, the boron sludge hydrolyzes and releases active Mg. 2+ At the same time, part of the amorphous silicon will precipitate in the form of silicic acid or silica gel. The chemical reaction formula is:

[0028] MgO+2H + →Mg 2+ +H2O

[0029] S2, add red mud-boron mud compound agent, maintain the pH to 8.5-9.5, react for 20-60 minutes, make NH4 + With PO4 3 - Under alkaline conditions with Mg 2+ Combine; continue to add compounding agent, free Na in red mud + OH - Rapidly increase the pH of wastewater to 9.0-10.0 to create the best crystallization window for struvite; at the same time, a small amount of hematite Fe2O3 plays the role of inducing eutectic: Fe 3+ With PO4 3- FePO4 is generated, and the lattice forms a heterogeneous coprecipitation nucleus with struvite MgNH4PO4. Free calcium ions accelerate the sedimentation of struvite. Ca 2+ Entering the struvite lattice to form calcium-doped struvite Ca x Mg 1-x NH4PO4;

[0030] In this embodiment, a red mud-boron mud compound (composition of red mud 50-70%, boron mud 20-30%, polyaspartic acid 0.5-2%, sodium carbonate 1-3%) is slowly added to the reaction tank, and the stirring device is turned on at the same time, and the stirring speed is controlled at 100-150r / min. During the addition process, the pH value of the wastewater is monitored in real time by a pH meter, and the pH value of the wastewater is adjusted to maintain at 8.5-9.5. The reaction time is 20-60 minutes. + With PO4 3- Under alkaline conditions with Mg 2+ Combined to form struvite, the chemical reaction formula is:

[0031] Mg 2+ +NH4 + +PO4 3- +6H2O→MgNH4PO4·6H2O↓(struvite)

[0032] Continue to add compound agent, free Ca in red mud 2+ 、Na + OH - Rapidly raise the wastewater pH to 9.0-10.0 to create the best crystallization window for struvite. A small amount of hematite (Fe2O3) plays the role of inducing eutectic: Fe 3+ With PO4 3- FePO4 is generated to form heterogeneous co-precipitation nuclei with struvite. Free calcium ions will also accelerate the sedimentation of struvite to form calcium-doped struvite. The chemical reaction formula is:

[0033] MgNH4PO4+xCa 2+ →Ca x Mg 1-x NH4PO4+xMg 2+

[0034] S3. The treatment solution is aged at 50-70° C. for 2-4 hours to form a stabilized structure of a Fe-OP chemical bonding layer, a silica gel physical coating layer, and a Ca-O-Si bridging network layer from the inside out.

[0035] In this embodiment, aging refers to allowing the solution to stand for a period of time under certain conditions after precipitation is complete. This is to allow the components to fully react and for suspended solids to settle. The treated solution is aged at 50-70°C for 2-4 hours to form a stabilized structure consisting of an Fe-OP chemical bonding layer, a silica gel physical coating layer, and a Ca-O-Si bridging network layer from the inside out, thereby extending the struvite's nitrogen and phosphorus release cycle.

[0036] The present invention also provides an aquaculture wastewater treatment device based on red mud-boron mud coordinated guano petrification, comprising: a reaction tank, a solid-liquid separation module, a dynamic control unit and a disinfection module.

[0037] The reaction pool is equipped with a multi-source sensor array to collect real-time time series data on wastewater turbidity (Hachsc200, 0-1000NTU, ±1%FS), pH value (±0.01pH, self-cleaning electrode), temperature (0-200mS / cm, ±0.5%FS), water level (±1mm, anti-foam interference), conductivity concentration (0-200mS / cm / ±0.5%FS, sampling frequency 1Hz), and stirring power (0-10kW / ±0.2%FS, sampling frequency 5Hz). The turbidity sensor should be installed away from the direct impact area of ​​the stirring paddle and 0.5-1m from the bottom of the pool to ensure the accuracy of the measurement data. The sensor is calibrated regularly, once a month, using standard turbidity solution for calibration. The pH sensor uses a self-cleaning electrode, and the electrode surface is cleaned regularly, once a week, using acidic and alkaline cleaning solutions alternately. Temperature sensors, water level sensors, and conductivity concentration sensors are regularly inspected and calibrated according to corresponding maintenance requirements to ensure proper function. The stirring device uses a paddle stirrer with a diameter of 1 / 3-1 / 2 the diameter of the reaction tank. The stirring shaft is made of stainless steel with an anti-corrosion surface treatment. The stirring motor is equipped with a frequency converter to adjust the stirring speed according to different processing stages.

[0038] The solid-liquid separation module is located at the bottom of the reaction tank and includes an ultrasonic enhancement zone, a progressive pressure dehydration zone, a special filter belt, and a non-contact air knife stripper. The piezoelectric ceramic transducers (28kHz transducer array) in the ultrasonic enhancement zone are installed at the bottom of the reaction tank and distributed in a circular pattern to ensure that the ultrasonic waves can evenly affect the wastewater. The power density of the transducers can be adjusted according to the actual treatment effect, with an adjustment range of 0.5-0.8W / cm 2 . A water level sensor is set. When the water level is ≥80% and the drainage signal is received, the ultrasonic generator is automatically triggered to work. The single action time is 30s and the interval time is 120s. Fixed; the actuator of the progressive pressure dehydration zone is a variable frequency drainage pump (frequency range: 30-50Hz), and the pressure gradient is 0.3bar to 1.5bar; the special filter belt is made of polytetrafluoroethylene coating, and the water permeable holes are diamond-shaped (pore size 50μm, porosity 45%); the non-contact air knife stripper has an air pressure of 0.6MPa and an angle of 30°.

[0039] The dynamic control unit utilizes an offline pre-trained bidirectional long short-term memory (BiLSTM) network model. Using Python and the PyTorch framework, time-series sensor data from the aquaculture wastewater treatment process was collected over three months (sensors collected data every 10 minutes, including turbidity, pH, temperature, water level, conductivity, concentration, and stirring power). This training dataset, encompassing different treatment stages and conditions, was constructed to enhance model generalization. After normalizing the data, a BiLSTM model was constructed consisting of an input layer, two LSTM layers (processing forward and reverse sequence data, respectively), and an output layer. The input layer's shape was determined based on the wastewater parameter dimensions and time step size, while the output layer had two neurons and a linear activation function. During training, the mean squared error (MSE) loss function was used to measure the difference between predicted and actual values. The Adam optimizer was used to automatically adjust the learning rate to improve training efficiency. The dataset was divided into training, validation, and test sets, with a 70%, 10%, and 20% split. The training set was used to adjust model parameters to minimize the loss function, while the validation set was used to monitor performance and prevent overfitting. After the model training is completed and saved, the new wastewater real-time data is preprocessed and input into the model, and the predicted values ​​of crystallization time and encapsulation degree are output. Based on these values, corresponding operations are triggered, such as starting the solid-liquid separation unit and adjusting the dosage of polyaspartic acid.

[0040] Model hyperparameter name Value Learning rate 0.001 Number of hidden units 64 Time step 10 Batch size 64 Number of cycles 50 Regularization coefficient 0.001

[0041] When the real-time running time is ≥ the predicted value of the crystallization time, the solid-liquid separation unit is triggered to start. The real-time running time refers to the running time of the equipment from the addition of the compounding agent to the end of the aging process; the dosage of polyaspartic acid is adjusted based on the predicted value of the encapsulation degree. If the predicted value of the encapsulation degree is less than 0.85, the dosage of polyaspartic acid is increased by 0.3-0.5% (accounting for the total weight of the system); if the predicted value of the encapsulation degree is ≥0.85, the current dosage is maintained.

[0042] The disinfection module includes a deep ultraviolet LED array (wavelength 265±5nm) and an ozone microbubble generator (concentration 0.5-2mg / L).

[0043] Example 1:

[0044] A certain competitive horse breeding base primarily focuses on the rearing and breeding of racehorses, with a permanent stock of 200 competitive horses. This breeding process generates a large amount of aquaculture wastewater, which contains high concentrations of pollutants such as nitrogen and phosphorus. If discharged without effective treatment, this wastewater will seriously pollute the surrounding aquatic environment and disrupt the ecological balance. To address this issue, the breeding base has introduced a method and apparatus for treating aquaculture wastewater based on the coordinated guano petrification of red mud and boron mud, as provided by the present invention.

[0045] The aquaculture wastewater is first separated into solid and liquid. The wastewater first passes through a mechanical screen with a bar gap of 4mm, which intercepts larger particles of solid impurities such as feed residues and feces. The wastewater then enters a horizontal flow sedimentation tank with a surface load controlled at 1.2m 3 / (m 2 ·h), the wastewater stays in the sedimentation tank for 1.8 hours to allow some suspended solids to settle further. The sedimentation tank is equipped with a backwash device, which is backwashed every 10 hours. The backwash water uses treated water that meets the standards, and the backwash intensity is 12L / (s·m 2 ).

[0046] After the pretreated wastewater is discharged into the reaction tank, dilute sulfuric acid with a concentration of 15% is used as a pH regulator and accurately added through a metering pump. The online pH meter monitors the pH value of the wastewater in real time. When the pH value reaches 6.0, the addition of dilute sulfuric acid is automatically stopped. A multi-point dosing device is set in the reaction tank, and the stirring device is turned on. The stirring speed is 80r / min and stirred for 8 minutes to ensure uniform pH adjustment. Boron mud is screened through a 100-mesh sieve and dried at 108°C to a moisture content of 9%. The boron mud is accurately weighed according to a ratio of 3% of the wastewater volume and evenly added to the reaction tank through a screw conveyor. The stirring device is turned on, the stirring speed is increased to 180r / min, and stirred for 35 minutes.

[0047] A red mud-boron mud compound was accurately weighed at a ratio of 60% red mud, 36% boron mud, 1.5% polyaspartic acid, and 2.5% sodium carbonate. Mix thoroughly in a mixer. Slowly add the compound to the reaction tank while stirring at 120 rpm. Adjust the wastewater pH to 9.0 and allow the reaction to proceed for 40 minutes.

[0048] Finally, it enters the aging stage, where the temperature is controlled at 60°C with an accuracy of ±1°C and the aging time is 3 hours.

[0049] The parameters before and after wastewater treatment are as follows:

[0050] index Water ingress Water Removal rate nitrogen 350mg / L 18mg / L 94.9％ phosphorus 45mg / L 0.9mg / L 98.0％ suspended matter 4200mg / L 33mg / L 99.2％

[0051] Example 2:

[0052] A large-scale pig farm with 5,000 pigs produces a large amount of wastewater daily during the breeding process. This wastewater is characterized by high levels of ammonia nitrogen, high levels of fat, and a tendency to foam. Compared to Example 1, the surfactants and fats in the wastewater in this example make it prone to foaming during treatment, which not only affects the normal operation of the equipment but also may cause secondary pollution.

[0053] Before the wastewater enters the subsequent treatment link, a pre-flotation tank is set up. Polyaluminium chloride (PAC) and polyacrylamide (PAM) are added to the flotation tank as coagulants and coagulant aids, with a PAC dosage of 80mg / L and a PAM dosage of 1.5mg / L. After the wastewater enters the flotation tank, a large number of tiny bubbles are generated through the dissolved air system, causing the grease and suspended matter in the wastewater to adhere to the bubbles, forming scum that floats to the water surface, and then is scraped off by a scraper. The hydraulic retention time of the flotation tank is controlled at 30 minutes, and the surface load of the flotation machine is 6m 3 / (m 2 h). Clean and maintain the flotation tank regularly to ensure stable flotation effect.

[0054] To address the impact of high oil content in wastewater on subsequent treatment, the boron sludge dosage was increased to 4.5% of the wastewater volume to compensate for losses caused by oil inclusion. Before use, the boron sludge was screened through a 120-mesh sieve and dried at 110°C to a moisture content of 8%. The boron sludge was evenly added to the wastewater treatment system via a screw conveyor. During addition, the agitator was activated at a speed of 100 rpm for 15 minutes to ensure thorough mixing of the boron sludge with the wastewater.

[0055] Adjust the red mud-boron mud compound to the following formula: 55% red mud, 40% boron mud, 2% polyaspartic acid, and 3% sodium carbonate. Accurately weigh each component in proportion and thoroughly mix in a mixer. Slowly add the compound to the reaction tank while turning on the stirring device and controlling the stirring speed at 150 r / min. Add an additional 10% of the mass of red mud added to the initial compound. Continue adding the compound to raise the pH of the wastewater to 9.7. Closely observe the formation of precipitation in the reaction tank. When the amount of precipitation no longer increases significantly, the reaction is basically complete.

[0056] A 28 kHz ultrasonic generator was set in the reaction tank, and the power density was set to 0.7 W / cm 2 When the wastewater enters the reaction tank, the ultrasonic generator is automatically turned on to perform ultrasonic treatment on the wastewater.

[0057] Ultrasonic treatment can break up foam in wastewater, ensuring efficient reaction. It also promotes full contact and reaction between the compounding agent and pollutants in the wastewater. During the dehydration process, pressure changes are monitored in real time via pressure sensors, automatically adjusting the pressure of the dehydration equipment based on the set pressure gradient.

[0058] The parameters before and after wastewater treatment are as follows:

[0059]

[0060]

[0061] Example 3:

[0062] A bullfrog farm has a stock of 10,000 frogs. The wastewater mainly comes from bullfrog excrement, residual feed, and regular water changes in the breeding ponds. It has the following characteristics: high ammonia nitrogen, high organic matter concentration, and a certain amount of plankton and algae.

[0063] Plankton removal: Use a microfilter (pore size 0.2mm) to perform preliminary filtration on the wastewater to remove large plankton and some algae, reducing the burden on subsequent treatment units.

[0064] pH adjustment: Since bullfrog breeding wastewater is weakly alkaline (pH about 8.5), dilute hydrochloric acid (7%) is added to adjust the pH to 6.2±0.2 to create a suitable acid-base environment for subsequent treatment reactions.

[0065] Boron mud activation: Add 300 mesh boron mud at 3.8% of the wastewater volume and stir for 45 minutes to fully activate the boron mud so that it can exert good adsorption and catalytic properties.

[0066] Compound agent addition:

[0067] The composition of the compound agent is: red mud 70% + boric mud 27% + polyaspartic acid 1.2% + sodium carbonate 1.8% (the proportion of ingredients is adjusted according to the characteristics of bullfrog wastewater).

[0068] Dosage calculation: According to Ca 2+ :PO43-=0.25:1 molar ratio, the dosage is determined to be 18kg / m 3 Wastewater.

[0069] Reaction condition control: The pH is stabilized at 9.0±0.3 through the pH automatic control system, and the reaction time is 50 minutes to ensure that the compounding agent fully reacts with the pollutants in the wastewater to generate a stable crystalline product.

[0070] Smart separation:

[0071] BiLSTM prediction: Based on wastewater parameters and real-time operation data, the BiLSTM model predicted a crystallization time of 62 minutes and a degree of encapsulation of 0.83.

[0072] Pressure gradient adjustment: Since the encapsulation degree is between 0.8-0.85, the pressure gradient is set to 0.5→0.9→1.2 bar. By gradually increasing the pressure, the solid-liquid separation efficiency is improved while avoiding excessive energy consumption.

[0073] Air knife stripping: Air knife stripping is performed at an air pressure of 0.55 MPa, with a stripping efficiency of 98.7%, effectively removing residual impurities and moisture attached to the surface of the crystallized product.

[0074] Aging and disinfection:

[0075] Aging treatment: The separated crystalline product was aged at 68°C for 3.5 hours to form a denser triple-coating structure, further reducing the solubility and release performance of the product.

[0076] Disinfection process: using UV dose 55mJ / cm 2 + Ozone 1.3mg / L, contact time 160 seconds, joint disinfection of treated water and crystallized products to ensure that the hygiene indicators of the effluent and products meet the relevant standards, with a sterilization rate of 99.98%.

[0077] The parameters before and after wastewater treatment are as follows:

[0078] index Water ingress Water Removal rate nitrogen 480mg / L 22mg / L 95.4％ phosphorus 85mg / L 1.0mg / L 98.8％ suspended matter 3600mg / L 92mg / L 97.5％ COD 3200mg / L 380mg / L 88.1％

[0079] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the original technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A method for treating aquaculture wastewater based on red mud-boron mud synergistic guano petrification, characterized in that: The following steps are involved: S1. After solid-liquid separation, the aquaculture wastewater to be treated is adjusted to pH 5.5-7.0, and boron mud is added and stirred for 10-60 minutes. The boron mud is hydrolyzed in the weakly acidic environment of the wastewater to release active Mg. 2+ , in which part of the amorphous silicon will be precipitated in the form of silicic acid or silica gel; S2, add red mud-boron mud compound agent, maintain the pH to 8.5-9.5, react for 20-60 minutes, make NH4 + With PO4 3 - Under alkaline conditions with Mg 2+ Combine; continue to add red mud-boron mud compound agent, free Na in red mud + OH - Rapidly increase the pH of wastewater to 9.0-10.0 to create the best crystallization window for struvite; at the same time, a small amount of hematite Fe2O3 plays the role of inducing eutectic: Fe 3+ With PO4 3- FePO4 is generated, and the lattice forms a heterogeneous coprecipitation nucleus with struvite MgNH4PO4. Free calcium ions accelerate the sedimentation of struvite. Ca 2+ Entering the struvite lattice to form calcium-doped struvite Ca x Mg 1-x NH4PO4; S3. The treatment solution is aged at 50-70° C. for 2-4 hours to form a stabilized structure of a Fe-OP chemical bonding layer, a silica gel physical coating layer, and a Ca-O-Si bridging network layer from the inside out.

2. The method according to claim 1, characterized in that The dosage of the boron mud in S1 is 1-5% of the volume of the wastewater, and the particle size of the boron mud is ≤200 mesh.

3. The method according to claim 2, characterized in that The composition of the red mud-boron mud compound is as follows by weight: 50-80% red mud, 20-50% boron mud, 0.5-2% polyaspartic acid, and 1-3% sodium carbonate.

4. The method according to claim 2, characterized in that The triple packaging structure formed in S3 satisfies: Inner layer: Fe-OP chemical bonding layer, Raman spectrum characteristic peak is located at 1085-1093cm -1 ; Middle layer: amorphous silica coating layer SiO2·nH2O, thickness 50-200nm; Outer layer: Ca 2+ Bridged Ca-O-Si network structure, Ca / Mg molar ratio 0.1-0.

3.

5. A farm wastewater treatment device based on red mud-boron mud synergistic guano petrification, characterized in that: include: Reaction tank, solid-liquid separation module, dynamic control unit and disinfection module; A multi-source sensor array is deployed in the reaction tank to collect real-time time series data of wastewater turbidity, pH value, temperature, water level, conductivity concentration and stirring power; The solid-liquid separation module is installed in the reaction tank and includes an ultrasonic enhancement zone, a progressive pressure dehydration zone, a special filter belt and a non-contact air knife stripper; The dynamic control unit outputs a crystallization time prediction value and a wrapping degree prediction value based on the time series data as input; when in operation, the dynamic control unit determines whether to start the solid-liquid separation unit based on the crystallization time prediction value; and the dynamic control unit adjusts the amount of polyaspartic acid added based on the wrapping degree prediction value; The disinfection module includes: an ultraviolet LED array and an ozone microbubble generator.

6. The device according to claim 5, characterized in that The ultrasonic enhancement zone is provided with a transducer array, and the transducer array dynamically adjusts the duration of action according to the change of water level; The pressure gradient of the progressive pressure dehydration zone is 0.3 bar to 1.5 bar; When the turbidity is greater than a preset turbidity value, the ultrasonic power is increased to a preset power value, and the pressure is reduced to a preset pressure value; The third-order pressure gradient is dynamically selected based on the predicted wrapping value. The selection of the third-order pressure gradient is associated with the numerical range of the predicted wrapping value, that is, the preset third-order pressure gradient parameter combination is matched according to the different ranges of the predicted wrapping value.

7. The device according to claim 6, characterized in that Dynamically selecting the third-order pressure gradient based on the predicted package degree value specifically includes: when the predicted package degree value is ≥0.85, adjusting the pressure gradient to 0.3→0.8→1.0 bar; when the predicted package degree value is 0.75-0.85, adjusting the pressure gradient to 0.5→1.0→1.3 bar; when the predicted package degree value is <0.75, adjusting the pressure gradient to 0.8→1.2→1.5 bar.

8. The device according to claim 5, characterized in that For mammalian wastewater, when the ammonia nitrogen concentration is 200–1500 mg / L and the COD is 5000–30000 mg / L, the weight ratio of red mud to boron mud should be controlled at 1:(0.5–1), and the reaction pH should be maintained at 8.5–9.

0. If heavy metals are detected that are greater than the limit, the red mud dosage should be increased by 10–20%. For crustacean wastewater, when the salinity is 3000–35000 μS / cm and the antibiotic residue is 1.5–5 mg / L, perform: When the salinity is greater than 5000 μS / cm, the amount of boron sludge added is increased by 15-25%; the disinfection module is activated to degrade antibiotics, and the ozone concentration is adjusted to 0.4 mg / L × the antibiotic concentration; For fish wastewater, when the suspended solids (SS) is 800–5000 mg / L and the total phosphorus (TP) is 20–200 mg / L, a vortex flotation pretreatment unit is added with an air-water ratio of 0.5:1, and the removal rate is >80%; For amphibian wastewater, when the pathogenic microorganism load is detected to be 10 3 –10 6 CFU / mL, and extend the disinfection time of the disinfection module by at least 1.5 times.

9. The device according to claim 5, characterized in that The dynamic control unit determines whether to start the solid-liquid separation unit based on the crystallization time prediction value, and then includes: if the real-time operation time is greater than or equal to the crystallization time prediction value, triggering the start of the solid-liquid separation unit, and the real-time operation time refers to the operation time of the equipment from the input of the compounding agent to the end of the aging process.

10. The device according to claim 5, characterized in that The dynamic control unit adjusts the amount of polyaspartic acid added based on the predicted value of the encapsulation degree, and then increases the amount of polyaspartic acid by 0.3-0.5wt% if the predicted value of the encapsulation degree is less than the preset value of the encapsulation degree; and maintains the current amount if the predicted value of the encapsulation degree is greater than or equal to the encapsulation degree.

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